On first impression, with just reading the part in the OP article saying the Cardinal is encouraging Catholics and Muslims to work together in overcoming violence among followers of different religions, I thought that the Cardinal’s message might be a groveling posture, a statement equating the wrongs by Catholics with the wrongs by Muslims, from the Crusades to the present, with which I do not find equivalence. But then, I decided that it could be a wrong impression on my part, so I called up the official letter of Cardinal Tauran from the Vatican site.
See here.
It is titled VATICAN MESSAGE TO MUSLIMS FOR RAMADAN. The Cardinal emphasizes that he is sending the goodwill of Christians, who are spiritually close to Muslims during these days. The letter is short, just 6 paragraphs. Notable is the first sentence “'Id Al-Fitr, which concludes Ramadan, presents, once again, a favorable occasion to convey to you the heartfelt wishes of serenity and joy on behalf of the Pontifical Council for Interreligious Dialogue.”
It is in line with the ongoing Catholic-Muslim dialogue, which had been ongoing in phases, especially after the Regensburg papal address controversy in September 2006. If you read the letter, you would find it to have the right tone and the right words, conciliatory, as expected.
Not that anybody is asking,

but I’m okay with it. I agree that we Catholics should wholeheartedly support the Vatican in its continuing message of peace to the Muslims as their holy month concludes.
I think the author in the OP linked article could have used a better header than
Cardinal encourages Catholics, Muslims to overcome violence.
But this quickness to self-flagellate by Catholics in this forum really astonishes me. I’m all for self-examination, repentance and rectification for actual wrongs. In all respect, I think we should be careful not to own sins Catholics did not commit, not in the name of the faith. I fail to see the attribution made to ‘Catholic’ hatred against the Protestants during the Troubles, as an example raised here. Unless historical accounts are wrong, it was an ethno-political feud in Northern Ireland that spilled out to England and parts of Europe.